Microprocessor controlled devices for scanning (reading) bar code symbols powered by batteries are known. As used herein, the term microprocessor refers to a central processing unit ("CPU") of a computer or microcomputer which is an integrated circuit and is used to control the operation of a processing system that performs data processing functions.
One such bar code reader includes a light generating and sensing circuit for reading a bar code, a microprocessor for processing the read bar code, and a power-supply circuit. The power-supply circuit connects the reader and a battery to provide power to the reader. Once powered, i.e., turned on, the reader continuously drains the battery regardless of whether or not the reader is actively reading bar codes. Another such bar code reader includes a slower microprocessor capable of shifting internally between a processing mode and an idle mode. During the processing mode, the microprocessor consumes battery power to process the read bar codes. During the idle mode, the microprocessor consumes less power as it remains idle. This version has a relatively reduced power consumption and has a longer useful life than the continuously operating version.
In recent years, however, high information density codes, such as two dimensional codes, including, for example, matrix codes, stacked bar codes and the like, have come into commercial use and acceptance. In some instances, two dimensional codes have replaced bar codes because bar codes cannot store as much information per unit area as the two dimensional codes. One such two dimensional code is an optically readable binary matrix code, as is more fully described with reference to U.S. Pat. No. 4,939,354, entitled "Dynamically Variable Machine Readable Binary Code and Method for Reading and Producing Thereof", commonly owned by the assignee of this patent document, and which is incorporated herein by reference.
One problem associated with utilizing two dimensional codes is that a relatively longer time is required to decode them because they contain more information than standard bar codes. Additionally, a problem exists in that, to decode these high density codes without considerable time delays, a high speed microprocessor is required, which acts to process quickly the scanned data to decode the symbol, and which thereby consumes a large amount of power. Unlike the reduced power consumption versions of the aforementioned conventional reader, many suitable high speed microprocessors are not designed with a low power consumption mode and, therefore, power consumption cannot be sufficiently reduced, even when data is not being decoded. Further, if the power-supply circuit connecting the portable code reader and a battery is arranged so as to be turned ON by a trigger switch, for example, when an operator wants to scan a code, a diagnostics check of the hardware components, common to high speed microprocessor processing systems, is repeated every time the microprocessor is activated by the trigger switch. Consequently, a considerable and noticeable time delay will be encountered after the trigger and before the start of a code read, or completion of a successful code read and decode operation. Excessive power consumption by selectively enabled microprocessor processing systems utilizing the high-speed microprocessor remains a continuing problem and obstacle to producing commercially useful portable, hand held scanning products, particularly in the two dimensional code field where the computational demands are great and the end user consumers expect nearly instantaneous read results. Relatively lengthy successful read delays are particularly commercially unacceptable in applications where the high density codes are being read while moving from one location to another and where performing diagnostic checks.
It is, therefore, an object of the present invention to provide apparatus, systems and methods for controlling the consumption of a power-supply by a selectively enabled processing system having a high speed microprocessor wherein the microprocessor does not include a low power consumption mode.
Another object of the present invention is to provide apparatus, systems and methods for performing diagnostics on a portion of a selectively enabled processing system when the power-supply is initially applied thereto, and thereafter operating an enabled processing system to process data without performing any diagnostics.
A further object of the present invention is to provide apparatus, systems and methods for permitting the selectively enabled processing system to consume the power-supply while processing data and to inhibit power consumption when data processing is complete.
A still further object of the present invention is to efficiently and inexpensively control consumption of power in selectably enabled high density code scanners.